1. Field of the Invention
The present invention relates to a bicycle, more particularly to a bicycle having a crank mechanism for adjusting position of a handle relative to a head tube.
2. Description of the Related Art
Referring to FIG. 1, a conventional bicycle 10 is shown to include a handle 13, a stem 12 that extends downwardly from the handle 13, and a head tube 111 which permits extension of the stem 12 therethrough to connect a fork assembly (not shown) that holds a front wheel thereon.
Since a pair of clamping plates 121, 122 is used to fasten the stem 12 on the handle 13, the latter cannot be tilted forwardly or rearwardly relative to the head tube 111, thereby inconveniencing the rider of the conventional bicycle 10 when he wishes to adjust position of the handle 13 relative to the head tube 111.
Therefore, the object of this invention is to provide a bicycle having a crank mechanism for adjusting position of a handle relative to a head tube so as to eliminate the aforesaid disadvantage associated with the prior art.
Accordingly, a bicycle of the present invention includes: a handle; a stem extending downwardly from the handle; a head tube; and a crank mechanism interconnecting the stem and the head tube. The crank mechanism includes a frame fixed on the head tube and having opposing front and rear ends, and a lever pivoted to the front end of the frame, extending uprightly therefrom and having an upper end. A crank is pivoted to the rear end of the frame, extends uprightly therefrom, and has an upper end. A coupler member is pivoted to the upper end of the crank, and is movably connected to the upper end of the lever so as to permit co-movement of the lever, the crank and the coupler member relative to the frame and so as to permit frontward and rearward movement of the handle together with the stem relative to the head tube. The bicycle further includes a locking unit selectively and movably connected to two of the frame, the lever, the crank and the coupler member, and operable between a locking position, in which the locking unit locks the crank, the lever, and the coupler member against movement relative to the frame, and an unlocking position, in which the locking unit releases the crank, the lever and the coupler member so as to permit co-movement of the lever, the crank and the coupler member relative to the frame and so as to permit adjustment of the stem to a desired position relative to the frame.